Some medications used to treat epilepsy and other conditions may increase the risk of suicide, a new study confirms.
The study, published in JAMA, the Journal of the American Medical Association, comes two years after the U.S. Food and Drug Administration issued an alert to warn that people taking certain anticonvulsant medications have twice the risk of suicidal behaviour and suicidal thoughts.
The FDA mandated at the time that labeling on the medications be changed to reflect the increased risk. But the decision was based on an analysis not large enough to investigate individual drugs.
This new study, led by a team from Brigham and Women's Hospital in Boston, identifies those medications that appear to carry the most risk.
The researchers analyzed data from almost 300,000 people aged 15 and older who had begun taking an anticonvulsant between July 2001 and December 2006. The meds they took included:
- Gabapentin
- Lamotrigine
- Oxcarbazepine
- Tiagabine
- Valproate
While the drugs are used primarily to control epileptic seizures, some have soared in popularity in recent years because they are also used for other conditions, including bipolar disorder, mania, migraine and chronic nerve pain.
"The wide range of indications and common use of anticonvulsants in pa¬tients with or without psychiatric co¬morbidities make their safety an issue of great relevance," the authors write.
The researchers recorded reports of suicide, attempted suicide or violent deaths in the first 60 days of use. They identified 827 suicidal acts (801 attempted suicides and 26 completed suicides) and an additional 41 violent deaths.
They found an increased risk of suicidal acts and violent deaths for the five drugs when compared with a standard anticonvulsant, topiramate. In most cases, the increased risk began about 14 days after the start of treatment.
There were 5.6 cases of attempted or completed suicide per 1,000 person-years among gabapentin users, 10 cases per 1,000 person-years among oxcarbazepine users and 14.1 cases per 1,000 person-year among tiagabine users compared with topiramate users.
While it's unclear why anticonvulsants increase the risk of suicidal behaviour, the medications are known to produce mood changes.
It should be noted though that many patients with psychiatric disorders and even patients with epilepsy have well-known increased risk for suicidal behaviour.
"This exploratory analysis contributes to the understanding of the complex and little-understood relationship between anticonvulsant medication use and suicide risk," the authors wrote. They didn't offer recommendations on whether prescribing practices for the medications should be altered.
